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December 07, 2006

Ned Seeman makes 'nanorobotic' arm to operate within DNA sequence

This is a major development for enabling mechanical control at the molecular level. Robert Freitas (who wrote nanomedicine) told Kurzweilai.net that he felt this was an evolutionary step towards the creation of a factory-style 'mechanical ribosome' system that could assemble biological parts via positional assembly.

New York University chemistry professor Nadrian C. Seeman and his graduate student Baoquan Ding have developed a DNA cassette through which a nanomechanical device can be inserted and function within a DNA array, allowing for the motion of a nanorobotic arm. The results, reported in the latest issue of the journal Science, mark the first time scientists have been able to employ a functional nanotechnology device within a DNA array.

The device, developed with NYU Chemistry graduate student Shiping Liao, emulates the process by which RNA replicas of DNA sequences are translated to create protein sequences. However, the signals that control the nanomechanical tool are DNA rather than RNA. The dimensions of the machine are approximately 110 x 30 x 2 nm.

In this study, Seeman and Ding developed a framework that contains a binding site--a cassette—that allows insertion of the device into a specific site of a DNA array. Changing the cassette’s control sequences or insertion sequences would allow the researchers to manipulate the array or insert it at different locations. The researchers added a long arm to the framework so that they could observe the structure undergoing a half-rotation. They visualized their results by atomic force microscopy (AFM), which permits features that are a few billionths of a meter to be visualized.

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